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                    NSFOCUS Security Advisory(SA2000-04)
     Topic£ºMicrosoft Win9x client driver type comparing vulnerability
                       Release Date£º August 20, 2000
                              Affected System:
                              ================
                           - Microsoft Windows 95
                           - Microsoft Windows 98
                   - Microsoft Windows 98 Second Edition
                           Non-affected system£º
                            ===================
                           - Microsoft Windows NT
                          - Microsoft Windows 2000
                                  Impact: 
                                 =========
     NSFOCUS security team has found a security flaw in Microsoft Win9x
      NETBIOS client. Exploitation of this vulnerability, a malicious
   attacker can modify his host file share service and perform DoS attack
                     to a Win9x client that visits it.
                               Description£º
                                ============
   When Win9x client accessing NETBIOS file shared services and comparing
       the driver types, if the returned type from server is none of
    below:"£¿£¿£¿£¿£¿"," A£º"," LPT1£º"," COMM"or"IPC"£¬it will lead to
   the sixth result, which is fake cause there are only five of them. So,
   win9x client will get a wrong driver pointer from conversion, transfer
    the control to the wrong driver function address and finally crash.
                                Workaround:
                            ====================
           Don't access the untrusted host's file share service.
                        Microsoft has been informed.
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                                 ==========
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                NSFOCUS Security Team <security@nsfocus.com>
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